1. **State the problem:** Solve for $c$ in the equation $c + 11 = 77$. 2. **Formula and rules:** To isolate $c$, subtract 11 from both sides of the equation. This uses the subtraction property of equality which states if you subtract the same number from both sides, the equality holds. 3. **Intermediate work:** $$c + 11 = 77$$ Subtract 11 from both sides: $$c + 11 - 11 = 77 - 11$$ Simplify: $$c = 66$$ 4. **Explanation:** We removed 11 from the left side to leave $c$ alone, and did the same on the right side to keep the equation balanced. The result is $c = 66$. **Final answer:** $c = 66$